904 extention housing bushing
You also need to unscrew the speedometer cable and remove the speedometer gear housing assy. or you take a chance on screwing up the speedometer gear when you slide the extension housing off and back on. Pishta is right about the big internal snap ring being a bugger to work with. I found a cheap set of very large (about 17" long) flat nose inside snap ring pliers at the local tool supply that work fantastic. Cost less that $20 too.